Flame-resistant thermoplastic molding compositions and moldings made therefrom

ABSTRACT

Highly flame-resistant thermoplastic molding compositions based on aromatic polycarbonates and including (1) small amounts of chlorine or bromine or alkali metal salts or nickel salts or of mixtures of chlorine or bromine and the salts and (2) small amounts of glass fibers. The molding compositions have good processability and high impact strength.

Umted Stat 1111 3,875,107 Nouvertn et al. Apr. 1, 1975 1 FLAME-RESISTANTTHERMOPLASTIC 3.112.292 11/1963 Bottenbruch et al. 260/47 MOLDINGCOMPOSITIONS AND 3,817,907 6/1974 Muller et al. 260/37 PC MQLDINQSMADE 2THEREFROM [75] Inventors: Werner Nouvertn, Krefeld,

Germanyi Peter QF Lyons, The Chemistry and Uses of Fire Retardents;coraopohs, 4 Gunter Pellswcker; Wiley-lnterscience 1970; pp. 420421,439. Hugo Vernaleken, both of Krefeld, I Germany 'Hattori et al.; TheEffects of Fiber Glass Reinforcement on the Flammability Properties ofThermoplas- [73] Asslgnee' Bayer Akhengesenschafl tics; Plastic Designand Processing; August 1967; pp

OTHER PUBLICATIONS Leverkusen, Germany 2.840 [22] Filed: Apr. 29, 1974[21] Appl. No.: 465,023 Primary Examiner-Lewis T.. Jacobs Related us.Application Data Attorney, Agent, or Firm-Lawrence S. Pope [62] Divisionof Ser. No. 293,195, Sept. 28, 1972, Pat.

[ ABSTRACT [30] Foreign Application Priority Data Sept. 29 1971 Germany2148598 H flame'reslstamFhermoplast'c m dmg tlons based on aromaticpolycarbonates and including [52] US CL... 260/37 PC, 106/15 260/47 XA(1) small amounts of chlorine or bromine or alkali 51 1111. c1 C08g51/10 metalsalts Salts F mixtures [58] Field of 260/37 106/15 bromineand the salts and (2) small amounts of glass fibers. The moldingcompositions have good process- [56] References Cited ability and highimpact strength.

UNITED STATES PATENTS 6 Claims, No Drawings 3,062.78l l [/1962Bottenbruch et al. 260/47 FLAME-RESISTANT THERMOPLASTIC MOLDINGCOMPOSITIONS AND MOLDINGS MADE THEREFROM This is a division ofapplication Ser. No. 293,195, filed Sept. 28, 1972 now US. Pat. No.3,845,007.

BACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to flame-resistant thermoplastic molding compositions and toarticles made therefrom.

2. Description of the Prior Art Various methods for reducing theflammability of aromatic carbonates from bis-hydroxy compounds areknown.

It has not proved successful to add flameproofing additives which areknown for other plastics, such as, for example, antimony trioxide, tohigh molecular thermoplastic carbonates of dihydric phenols, because theamount of such additives must be so great that the valuable propertiesof the polycarbonates are considerably impaired or the additives areincompatible with the polycarbonates or are unstable at the highprocessing temperatures of polycarbonates.

Additions of, for example, alkali or ammoniumperfluoroalkane-sulphonates, preferably those with perfluorinated alkylradicals with about 4-8 carbon atoms, which show good compatibility withthe polycarbonates and are sufficiently heat-stable (according to GermanOffenlegungsschrift 1,930,257) have proved more successful. Smalladditions of these sulphonates, in amounts of about 0.01 to about 1percent by weight, suffice to render the polycarbonates moreflame-resistant.

However, it has been found that the flame-resistant properties ofpolycarbonates containing the added alkali or ammoniumperfluoroalkane-sulphonates which have been mentioned in general do notyet suffice for practical requirements, and the grading, required formany instances of practical use, into a class of high non-flammabilityaccording to test methods, such as, for example, the burning testaccording to Underwriters Laboratories, item 94, is not achieved.

It is particularly the dripping behavior of a chemical material onexposure to flames which is important in as much as in cases of firethermoplastic compositions which burn with difficulty but drip whileburning, ignite substances which burn easily and can thus become thecause of greater damage. However, it has not yet been possible toimprove the dripping behavior of nonreinforced polycarbonates by theadditions of sulfonates which have been described.

A similar situation applies when using additions of nickel compounds (inaccordance with German Offenlegungsschrift 1,918,216).

Flame-resistant polycarbonates are hitherto preferentially manufacturedin industry by incorporating halogen-containing divalent phenols, forexample tetrachloroor tetrabromo-bisphenols into the polymeric molecule.The high halogen content which is required for grading in a category ofhigh fire resistance, for example SE 1 according to UnderwritersLaboratories, item 94, can, however, have adverse effects. (Compare US.Pat. No. 3,334,154). This is because the high halogen content causes aworsening of the processability of the polycarbonates in question, whichmanifests itself in diminished flow properties and reduced heatstability of these polycarbonates.

Glass fiber-reinforced aromatic polycarbonates of bis-hydroxy compounds,with a glass fiber content of 5 20 30 percent by weight, have proven tobe of value in practical use, since the glass fiber reinforcementproduces an improvement, relative to the non-reinforced polycarbonate,in a series of important properties such as, for example, the modulus ofelasticity and the flexural strength.

preferably 30 percent by weight of glass fibers.

Admittedly, the addition of glass fibers, in the amounts mentioned, toaromatic polycarbonates causes an embrittlement of the thermoplasticmolding composition and a substantial reduction in the impact 20strength as compared to the non-reinforced material.

Hence glass fiber additions of 20 30 percent by weight, such as are usedfor reinforcing aromatic polycarbonates from bis-hydroxy compounds andfor manufacturing dimensionally stiff thermoplastic moldingcompositions, are unsuitable for the manufacture of flameproofpolycarbonates having a high impact strength. On the other hand, glassfiber contents of less than '10 percent by weight when used as additivesto aromatic polycarbonates do not produce any improvements in the fireresistance.

SUMMARY OF THE INVENTION It has now been found, in accordance with thisinvention, that the high flame-resistant categories desired ofpolycarbonate molding composition, such as the SE 1 and SE 0classifications of Underwriters Laboratories, item 94, are achievedwithout appreciable effect on the processability or impact strength ofthe compositions by incorporating into the compositions 1) smallamountsof chlorine or bromine or of alkali metal salts or nickel saltsor of both the halogen and the salts and (2) small amounts of glassfibers.

The dramatic effect of the combination of glass fibers with halogen andor with salts is surprising because the amount of halogen or salts is,alone, generally not sufficient, in any case less sufficient to producean SE 1 or SE 0 flame-resistant polycarbonate composition and thesmall-amount of glass fibers would not be expected to improve theflame-resistant properties of the polycarbonate compositions.

DETAILED DESCRIPTION The flame-resistant thermoplastic moldingcompositions and articles provided according to this invention comprise,with the percentages given being by weight based on the total weight ofthe molding compositions:

a. from about 93 to 98 percent of an aromatic polycarbonate;

b. an effective amount of i. up to about 3 percent of chlorine orbromine, or

' ii. up to about 1 percent of alkali metal salts or nickel saltspreferably those salts soluble in the aromatic polycarbonate, or

iii. mixtures of i and ii; and

the flame-resistant polycarbonate molding compositions in the form ofhalogen-containing aromatic polycarbonates based on tetrachloroortetrabromobisphenol A-polycarbonates. The polycarbonates may behalogen-containing copolycarbonates alone or halogen-containingpolycarbonate homopolymers or copolymers mixed with halogen-freepolycarbonates,

The chlorine or bromine is incorporated into the polycarbonate moldingcomposition in amounts up to 3 per cent by weight, and preferably 1.5 to2.5 percent by weight, but if no flame-proofing additive is present, thechlorine or bromine should be at least 1 per cent by weight of themolding composition.

The alkali metal salts or nickel salts are incorporated into thepolycarbonate molding compositions in amounts up to 1 percent by weight,and preferably 0.05 0.2 percent but if no halogen is present, theflameproofing additive should be at least 0.01 per cent by weight of themolding composition.

It should be noted that the amount of l) chlorine or bromine and (2) thealkali metal salt or nickel salt used when both (l) and (2) are presentmay be less than the amount required for each when one of them is notpresent in the composition. The amount of (l) and (2) needed in amixture of (1) and (2) is that which will produce an SE 2 (explainedbelow) polycarbonate material when no glass fiber is present in thecomposition.

The glass fibers are incorporated into the polycarbonate moldingcompositions in amounts of from about 2 to 6% by weight and, preferably,about 4% by weight. The glass fibers useful in the invention haveaverage fiber lengths of 100 to 600 pm and, preferably, 200-400 um.

A particularly surprising fact is that even low viscosity polycarbonate,which flows easily and which tends to drip to an increased extent, canbe employed for the manufacture of the thermoplastic molding compositionaccording to the invention, with the additives according to theinvention preventing both a reduction in the smoldering times and alsothe undesirable dripping.

Because of the low glass fiber content, the high impact strength whichis demanded in many cases of practical use and is valued in aromaticpolycarbonates from bisphenol A is not worsened to any significantextent.

The small amounts of salts, flameproofing additives, and the small addedamounts of halogen also do not cause any decrease in the impact strengthwhich high impact strength is characteristic of polycarbonate.

The processability of the thermoplastic molding composition ofpolycarbonate is likewise not impaired to any significant extent by thesmall halogen content and glass fiber content according to theinvention.

Polycarbonates that may be used in the composition of. the invention,include those derived from aromatic bis-hydroxy compounds, and inparticular, for example, those manufactured from dihydric phenols, suchas resorcinol, hydroquinone or dihydroxydiphenyl, from bis-(hyroxyphenyl)-alkanes, such as, for example, bis-(4-hydroxyphenyl)-propane-2,2, from trinuclear bisphenols such as(1,0:-bis-(4-hydroxyphenyl)-p-diisopropylbenzene, from halogenatedbis-(hydroxyphenyl)-alkanes, such as, for example, 4,4-dihydroxy- 3 ,5,3,5 '-tetrachloro-phenylpropane-2,2 or 4,4- dihydroxy-3 ,5 ,3 ,5'-tetrabromo-phenylpropane-2,2, bis-(hydroxyphenyl)-cycloalkanes,-sulphones, -sulphoxides, -ethers and -sulphides, optionally mixed withglycols, with derivatives of carbonic acid, for example its diesters ordihalides, optionally with the conjoint use of minor amounts ofdicarboxylic acids or their derivatives which are suitable for theformation of an ester, and which possess an average molecular weight ofabout 10,000 to 100,000, preferably between about 20,000 and 50,000.

Suitable halogen-containing aromatic polycarbonates are, for example,copolycarbonates based on tetrachloroor tetrabromo-bisphenol-A andbisphenol-A or mixtures of halogen-free and halogen-containingpolycarbonate or co-polycarbonate.

Possible glass fiber materials are all commercially available types ofglass fibers, such as, for example, ground short glass fibers androvings, but especially staple glass fiber, provided that they possess afiber finish which is compatible with polycarbonate.

The additives to be used are the compounds which are known and suitablefor the flameproofing of polycarbonate. Also useful are synergisticallyacting substances.

Examples of suitable compounds are alkali salts having an organicmoiety, particularly those which are soluble in polycarbonate, and moreparticularly soluble alkali metal salts of organic carboxylic acids,preferably containing from 1 to 18 carbon atoms, and ofperfluoroalkanesulfonic acid. Examples of these salts include potassium2-ethyl-hexanate, sodium 2-ethylhexanate, lithium Z-ethyl-hexanate,potassium perfluorooctanate, sodium perfluorooctanate, lithiumperfluorooctanate, potassium salts of 5-ethyl-dioxan-l,3-yl-(5)-carboxylic acid, rubidium 2-ethyl-hexanate, rubidiumperfluorooctanate and potassium perfluoromethanesulfonate, potassiumperfluorooctanesulfonate and potassium perfluorobutanesulfonate. Furtherexamples of suitable salts are alkali salts of lauric acid, stearicacid, oleic acid, phthalic acid monobenzyl ester, adipic acid monobutylester, p-octylbenzoic acid, ptert.-butyl-benzoic acid,3-(3,5-di-tert.-butyl-4- hydroxyphenyl)-propionic acid and diglycollicacid mono-decyl ester.

Additionally, soluble nickel salts, for example the soluble nickel saltsof 2-ethyl-hexanoic acid, of lauric acid and of stearic acid may beused.

The glass fiber materials, like the flameproofing additives andhalogen-containing polycarbonates described, can be added to thepolycarbonates in various ways. They can be added to the reactionmixtures before, during or after the manufacture of the polycarbonates.They can furthermore be added to polycarbonate solutions orpolycarbonate melts. Finally, they can be mixed with polycarbonategranules and these mixtures can be homogenized by subsequent meltextrusion.

In the same manufacturing process it is possible to add to thepolycarbonate, in addition to the additives according to the invention,further additives such as, for example, the pigments and effectsubstances suitable for coloring the polycarbonate, and also moldreleaseagents, stabilizers and anti-oxidants.

The surprising influence of the additive combination according to theinvention on the fire resistance of aromatic polycarbonates based onbisphenol A, while retaining the impact strength characteristic of suchpolycarbonates, is illustrated by Tables 1 3. The undesired reduction inthe impact strength caused by high amounts of glass fibers isrecognizable. The flameresistant polycarbonates according to theinvention can be processed in the form of powders or granules, inaccordance with the known processing methods, such as, for example, byinjection molding or extrusion, to give moldings of the most'diversekind.

Molding compositions from the flame-resistant thermoplasticpolycarbonates according to the invention, which contain the additivesaccording to the invention, are suitable for the manufacture ofimpact-resistant moldings of low flammability such as are employed, forexample, in general instrument construction, precision engineering, theelectrical industry and telecommunication, and also for the manufactureof semifinished goods, such as, for example, films, sheets, rods andprofiles.

EXAMPLES Tables 1, 2 and 3 contain Examples 1 to 20. Examples markedwith an asterisk do not relate to compositions of the invention and areincluded for comparison only.

In Tables 1 and 2 the results of flammability tests according tostandards of Underwriters Laboratories, item 94 (UL 94), and IBM6-0430-102, are listed.

In the UL 94 test individual specimens of the dimension 1/16 X k X 5inches are vertically clamped and exposed twice for 10 seconds each timeto a blue gas flame of 20 mm height, the top of the gas burner ispositioned about 10 mm from the lower end of a test specimen. Thespecimens are positioned 12 inches above a horizontal layer of absorbentsurgical cotton. For classifying the material in a fire class, 5 testpieces in the injection-fresh and in the tempered state (tempering iscarried out at 70C for 7 days) are tested.

The following criteria are decisive for classification:

After burning times correspond to those of SE2 but 5 25 seconds 30seconds material may not drip off burning.

Average after-burning time Maximal acceptable after-burning time: Thematerial must not drip off burning s seconds seconds In the IBM6-0430-102 test, test specimens measuring 120 X 10 X 4 mm are suspendedvertically and exposed to a 2 cm high Bunsen burner flame (without anair supply). The distance of the top of the Bunsen burner is 1 cm fromthe bottom of the test specimen. The length of time is determined forwhich a test specimen can be exposed to the flame as described abovewithout continuing to burn for longer than 30 seconds after removal ofthe flame, and without burning particles dripping off of the specimenand igniting a wad of cotton wool placed under the specimen. A materialis classed as a Class A material if after a 60 second flame applicationtime, the material will extinguish without producing flaming droplets.Class B materials are those that extinguish within 30 seconds after a 5second or more flame application time but cannot withstand a 60 secondflame application time without exceeding the foregoing. Thus, forexample if a material extinguishes within 30 seconds for flameapplication times up to 45 seconds it is classified Class B/4 mm/45 see.

In the examples the polycarbonates described (granulate'd) are dry mixedwith the various amounts of flame" proofing additive, e.g., in the formof the tetrachlorobisphenol A polycarbonate, or glass fibers by socalledtumbling. Thereafter, the granules are extruded at about 300 C., using amixing screw, to give a ribbon that is then chopped to give granules.These granules are then converted into the required test sepcimens in aninjection molding machine at about 300C. 7

The halogen-free polycarbonate of bisphenol A employed in Examples 1-20is the reaction product of bisphenol A and phosgene having a relativeviscosity of 1.28 measured on solutions of 0.5 g of polycarbonate in mlof methylene chloride at 25C. It is prepared by introducing undernitrogen atmosphere, 1825 parts by weight of phosgene into a mixture of3420 parts by weight of bisphenol A, 70.0 parts by weight of p-tert.butylphenol, 2100 parts by weight of a 45 per cent by weight aqueoussodium hydroxide solution, 17,500 parts by weight of distilled water and33,000 parts by weight of methylene chloride at 2425C. During the 10thand 90th minutes of the introduction period of phosgene further 1300parts by weight of a 45 percent by weight aqueous sodium hydroxidesolution are dropped in. After the introduction of the phosgene isfinished 6 parts by weight of triethylamine are added and stirredfurther for an hour. Then the organic phase and the aqueous phase areseparated. The organic phase is washed first with a 2 percent by weightaqueous phosphoric acid, second with a 2 percent by weight aqueoussodium hydroxide solution, third further two times with the 2 percent byweight phosphoric acid and finally with distilled water until thesolution is neutral. Thereafter 7500 parts by weight of chlorobenzene isadded to the methylene chloride solution and the main proportion ofmethylene is distilled off. After cooling the remaining mixture gellsand the gel is chopped to small pieces which are dried at C. undervacuum during 48 hours.

The polycarbonate of bisphenol A and tetrachlorobisphenol A employed inExamples 1-9 has a relative viscosity of 1.27 and contains 6.5 percentchlorine. This product is prepared by treating a mixture of 2.992 partsby weight of bisphenol A, 686 parts by weight of tetrachlorobisphenol A(2.2-bis-(3,5- dichloro-4-hydroxyphenol)-propane), 50 parts by weight ofp-tert. butylphenol, 2850 parts by weight of a 45 percent by weightaqueous sodium hydroxide solution, 17,500 parts by weight of distilledwater and 33,000 parts by weight of methylene chloride with phosgene andby working-up the reaction product as described above for thehalogen-free polycarbonate.

The polycarbonate of bisphenol A and tetrabromobisphenol A employed inExamples 10 16 has a relative viscosity of 1.293 and contains 6 percentbromine. This product is prepared by reacting 3246 parts by weightbisphenol A, 414.parts by weight of tetrabromobisphenol A, 54 parts byweight of p-tert.-butylphenol, 4300 parts by weight of 45 percent byweight of sodium hydroxide solution with the parts by weight of theremaining compounds set forth above for the tetrachlorobisphenolA-polycarbonate; the reaction product is worked up as described abovefor the halogenfree polycarbonate of bisphenol A.

The other copolycarbonates mentioned therein are prepared accordingly.

Table 1 Optimizing the fire resistance, while retaining the im actstrength of polycarbonates based on bisphenol A, by adding chlorine inthe form of tetrachloro isphenol-A-polycarbonate and/or glass fibers.

Burning test in accordance with Underwriters Laboratories Inc Impactstrength-ll-) Chlorine Glass fiber Average Number of burning lBMaccordin to content in 70 content in smoldering time samples which haveClassification subj. CMl-l DIN 53 53 by weight by weight in secondsdripped 6-0430-102 cmkp/cm 1* 25 20 not self- Cl. B 4 mm/ did not breakextinguishing l secs 2* 7 0 SE I Cl. A 4 mm/ 49 60 secs 3* 4 15 notself- Cl. B 4 mm/ did not break extinguishing 15 secs 4 4.5 l0 7 SE llCl. B 4 mm/ did not break 20 secs 5* 4.5 4 6 0 SE l Cl. A 4 mm/ did notbreak 60 secs 6* 4.5 6 3 0 SE 0 Cl. A 4 mm/ 93 60 secs 7* 2.25 20 12 notself- Cl. B 4 mm/ did not break extinguishing 20 secs 8 2.25 3 l l 0 SE1 Cl. B 4 mm/ did not break secs 9 2.25 4.5 4 0 SE 0 Cl. A 4 mm/ did notbreak 60 secs 20 flame exposures were carried out in each case H-) l0samples were tested in each case Table 2 Optimizing the fire resistance,while retaining the impact strength of polycarbonates based on bisphenolA, by addingtbromine in the form of tetrabromobisphenol-A-polycarbonateand/or glass fibers.

Burning test in accordance with Underwriters Laboratories lnc+) lmpactStrength++) Bromine Glass fiber Average Number of burning lBM accordingto content in 7! content in smoldering time samples which haveClassification subj. CMH DlN 53 453 by weight by weight in secondsdripped 6-0430-102 cmkp/cm l0 25 20 not self- Cl. B 4 mm/ did not breakextinguishing l0 secs 1 1* 20 7 0 SE l Cl. A 4 mm/ 49 60 secs l2 4 25 l5not self- Cl. B 4 mm/ did not break extinguishing l5 sees 13* 6 8 5 SEll Cl. B 4 mm/ did not break secs 14* 6 5 2 0 SE 0 Cl. A 4 mm/ did notbreak 60 secs l5* 3 8 9 SE ll Cl. B 4 mm/ did not break 40 secs l6 3 4 20 SE 0 Cl. A 4 mm/ did not break 60 secs 20 flame exposures were carriedout in each case -H-) H] samples were tested in each case Table 3Optimizing the fire resistance while retaining the impact strength ofpolycarbonates based on bisphenol A by adding flameproofing additivesand/or glass fibers.

Burning test in accordance with Underwriters Laboratories Inc.+)

Additive content impact strength-1+) (K perfluoro- Glass fiber AverageNumber of burning according to octanesulphonate) content in smolderingtime samples which have Classification DlN 53 453 in by weight by weightin seconds dripped cmkp/cm l7 0.l 5 6 SE ll did not break 18 2O 7 0 SE l49 i9 S 6 2 SE ll did not break 20 0.l 5 4 0 SE 0 did not break 20 flameexposures were carried out in each case -H-) l0 samples were tested ineach case EXAMPLE 21 0.1 percent by weight of potassiumperfluorobutanesulfonate and percent by weight of glass fibers ofaverage length 400 um were incorporated into a copolycondensate ofbisphenol A and tetrachlorobisphenol A containing 0.9 percent by weightof chlorine to give a molding composition. Appropriate test rods fromthe molding composition thus obtained conform to Class I of the firetest according to Underwriters Laboratories, subject 94, and are ratedClass B/4 mm/45 secs. according to IBM Fire Test Subject CMI-I6-0430-102. Test specimens corresponding to the standard specificationdo not break in the impact test according to DIN 53,453.

EXAMPLE 22 0.2 percent by weight of potassium isooctanate and 6 percentby weight of glass fibers of average length 110 um are mixed into thepolycarbonate of bisphenol A to give a molding composition. Appropriatetest specimens of the molding composition thus obtained conform to Class1 of the fire test according to Underwriters Laboratories, subject 94,and are rated Class B/4 mm/4O secs. according to IBM Fire Test SubjectCMH 6-0430-102. Some of the test specimens break in the impact testaccording to DIN 53,453 while the rest do not break.

EXAMPLE 23 0.5 percent'by weight of nickel laurate and 4 per cent byweight of glass fibers of average length 400 ,um are mixed into thepolycarbonate from bisphenol A to give a molding composition.Appropriate test specimens of the molding composition thus obtainedconform to Class I of the fire test according to UnderwritersLaboratories, and are rated Class B/4 mm/45 secs. according to IBM,Subject CMH 6-0430-102. Test specimens corresponding to the standardspecification do not break in the impact test according to DIN 53,453.

EXAMPLE 24 EXAMPLE 25 0.1 percent by weight of sodium perfluorooctanateand 4 percent of glass fibers of average length 400 um are mixed intothe polycarbonate from bisphenol A to give a molding composition.Appropriate test specimens of the molding composition thus obtainedconform to Class 1 of the fire test according to UnderwritersLaboratories, subject 94, and are rated Class B/4 mm/4O secs. accordingto IBM, Subject CMH 6-0430-102. Test specimens corresponding to thestandard specification do not break in the impact test according to DIN53,453.

EXAMPLE 26 0.05 percent by weight of potassium perfluorooctane-sulfonateand 5 percent by weight of glass fibers of average length 550 um areadded to a polycarbonate from bisphenol A to give a molding composition.Appropriate test specimens of the molding composition thus obtainedconform to Class 1 of the fire test according to UnderwritersLaboratories, subject 94, and are rated Class B/4 mm/4O secs. accordingto IBM, Subject CMH 6-0430-102. Test specimens according to the standardspecification do not break in the impact test according to DIN 53,453.

Thus from the examples it is seen that the molding compositions of theinvention exhibit unexpected flame-retardant or flame-resistantproperties but still retain a high impact strength and goodprocessability.

It is to be understood that any of the components and conditionsmentioned as suitable herein can be substituted for its counterpart inthe foregoing examples and that although the invention has beendescribed in considerable detail in the foregoing, such detail is solelyfor the purpose of illustration. Variations can be made in the inventionby those skilled in the art without departing from the spirit and scopeof the invention except as is set forth in the claims.

What is claimed is:

1. A high impact, flame resistant aromatic polycarbonate containing byweight:

a. 2-6 percent glass fibers having an average fiber length of to 600 um;and

b. an effective amount of i. up to 3 percent of chlorine or brominechemi-' cally bonded to an aromatic carbon atom of said aromaticpolycarbonate, and ii. up to 1 percent of an alkali metal salt.

2. The aromatic polycarbonate of claim 1 wherein said alkali metal saltis soluble in said aromatic polycarbonate.

3; The aromatic polycarbonate of claim 1 wherein i is present in anamount of l to 3 percent, and ii is present in an amount of about 0.01to 1 percent.

4. The aromatic polycarbonate of claim 1 wherein said chlorine orbromine is present in an amount of from 1.5 to 2.5 percent.

5 The aromatic polycarbonate of claim 3 wherein said alkali metal saltis present in an amount of from 0.05 to 0.2 percent.

6. Articles molded from the composition of claim 1.

1. A HIGH IMPACT, FLAME RESISTANT AROMATIC POLYCARBONARE CONTINING BY WEIGHT: A. 2-6 PERCENT GLASS FIBERS HAVING AN AVERAGE FIBER LENGTH OF 100 TO 600 UM; AND B. AN EFFECTIVE AMOUNT OF I. UP TO 3 PERCENT OF CHLORINE OR BROMINE CHEMICALY BONDED TO AN AROMATIC CARBONATOM OF SAID AROMATIC POLYCARBONATE, AND II. UP TO 1 PERCENT OF AN ALKALI METAL SALT.
 2. The aromatic polycarbonate of claim 1 wherein said alkali metal salt is soluble in said aromatic polycarbonate.
 3. The aromatic polycarbonate of claim 1 wherein i is present in an amount of 1 to 3 percent, and ii is present in an amount of about 0.01 to 1 percent.
 4. The aromatic polycarbonate of claim 1 wherein said chlorine or bromine is present in an amount oF from 1.5 to 2.5 percent.
 5. The aromatic polycarbonate of claim 3 wherein said alkali metal salt is present in an amount of from 0.05 to 0.2 percent.
 6. Articles molded from the composition of claim
 1. 